PUEBLO, Colo. — Heather Surovik’s story is heartbreaking. In 2012, the young mother was leaving her final prenatal appointment when a drunk driver slammed into her car. Heather survived. The fetus she was carrying, whom she had named Brady, did not. The doctors told her that Brady weighed 8 pounds, 2 ounces.

Under Colorado law, the drunk driver was charged with felonies for his actions, but nothing in connection with Brady’s death. State law does not recognize crimes committed against fetuses. Now, Surovik is pushing an amendment to the state constitution, Amendment 67, that would include crimes against the unborn in Colorado’s criminal code.

The “personhood” amendment is nothing new. Colorado voters have twice defeated prior initiatives to extend rights to unborn fetuses. What is new is the approach: Earlier versions defined a fetus as a person from the moment of fertilization, or from the moment of biological development. In both cases, abortion rights activists convinced voters to reject the measures, which they said would have limited a woman’s right to choose.

This version, though, would allow prosecutors to bring charges against someone who commits a crime against a fetus. Proponents are going out of their way to insist that the measure has nothing to do with abortion, and some abortion rights advocates think the simplicity of the measure is cause for concern.

“Amendment 67 corrects the loophole in Colorado law and ensures that those criminals can be charged with killing a child in many different scenarios, whereas previous personhood amendments didn’t address the criminal code,” said Jennifer Mason, a spokeswoman with PersonhoodUSA, the group backing the amendment.

“To the folks on the other side, it is all about abortion to them,” she said. “To Heather Surovik, this is about recognizing every human life, about making sure every Colorado woman and child are protected.”

At the annual Colorado State Fair on a recent Friday afternoon, a volunteer passing out literature at the pro-Amendment 67 tent struck a similar chord. Asked whether the amendment was about abortion, the woman shook her head: “No, it’s about the criminal code,” she said.

Planned Parenthood has launched a huge campaign to beat back this third attempt to enshrine personhood in Colorado’s constitution. The group’s state chapter plans to spend at least $3.8 million on voter education, including $1 million on field organizing and voter education.

“This particular amendment is different from the ones we’ve seen before in terms of language. When voters read it, because the language mentions the protection of the pregnant woman in the first two lines, they believe that’s what it’s about,” said Cathy Alderman, vice president of public affairs at Planned Parenthood of the Rocky Mountains and Planned Parenthood Votes Colorado.

The challenge, Alderman said, is to equate the criminal code with personhood language.

“We need to meet voters where they are in terms of their values, and that’s a little bit different from just saying vote no on personhood,” she said. “They don’t really see this measure as having that impact. They don’t understand that it’s personhood.”

PersonhoodUSA, Mason said, isn’t able to match Planned Parenthood’s spending. Mason’s group is grassroots-oriented, and they haven’t attracted the funding to launch a serious paid advertising campaign.

While pro-choice advocates struggle with voter education, Democrats running elsewhere on the ticket aren’t terribly upset with the amendment’s presence on the ballot. Sen. Mark Udall (D) has used personhood to try and drive a wedge between his opponent, Rep. Cory Gardner (R), and women voters. The more women — especially young, single women — who turn out, the better it is for Udall.

“Personhood doesn’t represent a majority of Coloradans’ point of view. So it’s a significant debate,” Udall said in an interview here.

Gardner also opposes the amendment, he said in an interview. But that hasn’t stopped Democrats: In their first advertisement in Colorado, released last week, the Democratic Senatorial Campaign Committee accuses Gardner of backing amendments to the U.S. Constitution that would have prohibited all abortions.

Abortion rights advocates hope they can make the same sale, to the same voters. But it won’t be as easy as in years past.

“We can get voters to a ‘no’ vote, we just have to explain it in a little more detail,” Alderman said.